Field of the Invention
Energy costs, particularly as illustrated by the cost of crude oil and liquid petroleum distillates derived from crude oil have escalated rapidly. These costs are especially burdensome to the users of transportation fuels who are major consumers of petroleum products and they are reacting by searching for more efficient measures to use in their operations. One significant development in the transportation field including over-the-road and marine propulsion units is the trend toward engines which are relatively more fuel efficient with respect to petroleum fuel compositions.
Crankcase lubricating oil compositions for gasoline engines and for medium and high speed diesel engines must possess a number of essential characteristics in order to be operable and to maintain their effectiveness for a satisfactory period of time. In general, such a lubricating oil composition must possess alkalinity expressed as Total Base Number ranging from about 5 to 40 TBN, anti-wear properties, dispersancy, good viscosity index properties, VI improver, oxidation inhibition and demulsifying properties.
The need to improve efficiency in the use of oil has spurred intensive efforts to discover a crankcase lubricating oil composition which can materially reduce the friction losses which take place within the engine itself. A reduction in engine friction losses translates directly into significant fuel savings. Numerous means have been employed to reduce the friction inside an internal combustion engine. These range from the use of a lower viscosity crankcase lubricating oil or a mixture of mineral and synthetic lubricating oils as well as to the incorporation of friction-reducing additives, such as graphite, molybdenum compounds and other chemical additives. There are limits to the extent to which the viscosity of a lubricating oil can be reduced for the purpose of reducing friction. Generally, a lubricating oil having too light a viscosity will fail to prevent metal-to-metal contact during high load operating conditions with the result that unacceptable wear will occur in the engine. With respect to chemical anti-friction additives, significant research efforts are ongoing to find effective and economic anti-friction additives which exhibit stability over an extended service life and under a wide range of operating conditions.
It is an object of this invention to provide a novel crankcase lubricating oil composition for medium and high speed engines.
It is another object of this invention to provide a crankcase lubricating oil composition having improved friction properties for lubricating medium and high speed engines.